Device and method for sealing puncture wounds

ABSTRACT

A device is proposed for inserting hemostatic material through a tissue channel and against the outside wall of a blood vessel of a patient, wherein the blood vessel wall has a puncture therein adjacent the tissue channel. The device includes a charge of hemostatic material and a hollow sheath adapted to pass through the tissue channel, the sheath having a cross sectional profile larger than the puncture. The device places the hemostatic material in the hollow sheath and advances the hemostatic material through the sheath to the outside of the vessel wall around the puncture.

This is a continuation of application Ser. No. 08/318,380, filed on Oct.5, 1994, which is a divisional of application Ser. No. 07/746,339, filedon Aug. 16, 1991, now U.S. Pat. No. 5,391,183, which is acontinuation-in-part of application Ser. No. 07/634,478, filed on Dec.27, 1990, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the invention

The present invention relates to a method for sealing a puncture woundin a blood vessel and a device for practicing said method.

2. Related Background

In certain medical procedures, such as cardiac catheterization,dilatation and counterpulsation, a catheter or other device is insertedinto an artery, most commonly by percutaneous methods, and then fedthrough the arterial tree to the site where needed, frequently, theregion of the heart. The site usually selected for insertion is thegroin, because the femoral artery in that region is relatively easy tolocate.

These procedures are normally initiated by insertion of an angiographicneedle, followed by passing a guide wire through that needle into theartery. The needle is then removed leaving the guide wire in place.Next, a sheath-dilator set is passed over the guide wire into the arteryin order to enlarge the opening sufficiently to permit entry of thecatheter or other device. The dilator is then removed, leaving thesheath or guide cannula in place. The catheter or other device can thenbe inserted through the cannula with full confidence that when itemerges from the distal end it will be within the lumen of the artery.

It should be understood that the subject invention is independent of thenature of the medical device being used to treat the patient.Accordingly, the term "catheter" will be used here in a very generic andbroad way to include not only "catheters" in the strict sense, but anydevice that is inserted into a blood vessel of the body.

Similarly, the subject invention is independent of the blood vesselinvolved. While it is anticipated that the femoral artery will be themost commonly used blood vessel, other arteries as well as veins mightjust as easily be involved.

After a procedure, for example, counterpulsation, has been completed,the sheath must be removed and the wound closed. Often, this can beaccomplished simply by the application of digital pressure, generallyaugmented by the use of a pressure dressing. Customarily, pressure mustbe applied for at least 1/2 hour, and frequently for much longer thanthat. While pressure dressings often suffice, it is not uncommon foradditional devices, such as sandbags, to be needed. In addition, duringthis period the patient must be immobilized, lest movement interferewith the closing process. Because of the pressure required, the timeduring which it must be applied and the need for immobilization, theprocedure is painful and uncomfortable.. It also requires prolongedpersonal attention of a health care professional. Finally, woundclosures accomplished in this manner are prone to reopen unexpectedlylong after closure appears to have been completed. Patients aretherefore often required to remain in the hospital for 24 hours orlonger.

Because sealing can be such a problem, cardiologists tend to use thesmallest calibre catheters when performing catheterization procedures.Larger calibre catheters, however, are far preferable. An improvedsealing procedure whereby larger catheters can be used withoutincreasing the sealing difficulties would greatly facilitate cardiaccatheterization.

A series of related devices which were designed to address some of theseproblems is described in U.S. Pat. Nos. 4,744,364, 4,852,568 and4,890,612. These three patents describe a mushroom or umbrella shapeddevice which is used to seal the artery from the inside. The head of thedevice is placed within the arterial lumen and means are provided topull and hold the underside of the head against the inside wall of thelumen. It is believed, however, that sealing from the inside can be thesource of its own problems, including the promotion of clot formationinside the vessel.

Another method for sealing a puncture wound is described in U.S. Pat.No. 4,929,246. The approach taken there is to insert a balloon-tippedcatheter into the tissue wound, inflate the balloon against the hole inthe artery and then use a laser to thermally weld the wound closed.

The present invention is believed to overcome most of the drawbacks ofthe traditional method, without creating any new difficulties. This isaccomplished by using a plug, preferably a collagen plug or plug of someother resorbable material, to seal the artery along its outside wall.

SUMMARY OF THE INVENTION

In its most simplified form, the instant invention involves the placingof hemostatic material against the outside wall of a punctured artery.The hemostatic material covers the entire puncture site and a hemostaticseal is formed so as to stop bleeding from the puncture wound.

In one embodiment, the subject invention teaches the use of a plug,preferably of fibrous collagen material. The plug is inserted into thetissue wound and is held against the outside of the artery wall so as tooverlap the puncture wound. Before plug insertion, the artery ispreferably clamped by the use of external digital pressure, at a pointslightly upstream of the wound site. After the plug has been inserted,the upstream clamping pressure is maintained for a very short period oftime, and then gently removed. Slight pressure may be maintained on theplug to hold it against the artery wall until a good seal has beenestablished.

In order to insert the plug in accordance with the procedure outlinedabove, a special device has been designed. It is comprised of two basiccomponents, a sheath and a plug pusher or piston. The sheath is insertedthrough the tissue until its leading end is near to or abuts the outerwall of the artery. Thereafter, the plug is advanced through the sheathby use of the plug pusher until the plug abuts the artery wall andoverlaps the arterial puncture on all sides. Finally, after a good sealhas been established, the sheath and pusher are removed.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an exploded view of one embodiment of an insertion apparatusin accordance with the instant invention.

FIG. 2 depicts, in cross section, one embodiment of an insertionapparatus in accordance with the instant invention.

FIG. 3 depicts, in cross section, a second embodiment of an insertiondevice in accordance with the instant invention.

FIG. 4 depicts, in cross section, an exploded view of a third embodimentof an insertion apparatus in accordance with the instant invention.

FIG. 5 is an enlarged, schematic drawing, in cross section, of aninsertion site, showing a balloon catheter, having passed over a guidewire through a guide cannula into the femoral artery of a patient.

FIG. 6 shows the insertion site of FIG. 5 after the catheter and cannulahave been removed.

FIG. 7 shows the insertion site of FIG. 6 after insertion of a tissuedilator in accordance with the instant invention.

FIG. 8 shows the insertion site of FIG. 7 after insertion of a sheathover the tissue dilator in accordance with the instant invention.

FIG. 9 shows the insertion site of FIG. 8 after removal of the tissuedilator and guide wire and after partial insertion of a hemostatic plugand plug pusher.

FIG. 10 shows the insertion site of FIG. 9 after the hemostatic plug hasbeen pushed out of the sheath and while it is being held in intimatecontact with the arterial puncture.

FIG. 11 shows an alternative embodiment of the instant invention whereina collagen balloon is used to seal an arterial puncture.

FIGS. 12a, b, c, d and e show alternative forms of plug which are usefulin practicing the instant invention.

FIGS. 13 through 23 show the steps of an alternate procedure forpracticing the instant invention.

DETAILED DESCRIPTION

In certain procedures, for example, intra-aortic balloon pumping("IABP"), percutaneous translumina coronary angioplasty ("PTCA") andangiography, as best seen in FIG. 5, a catheter or other device 7 isinserted, often over a guide wire 15, through a guide cannula 3 into anartery 11, most frequently, the common femoral artery in the groin areaof the patient's leg 1. When the procedure (e.g., counterpulsation) hasbeen completed, the device (e.g., the catheter), the guide wire and theguide cannula must be removed and the wound closed.

In accordance with one embodiment of the instant invention, wounds ofthis type are closed by inserting a plug 57 into tissue wound or channel9, and holding it against the outside of the artery wall over arterialpuncture 13 for a short period of time until a good self-sustaininghemostatic seal is established. Although punctures of the sort made bypercutaneous procedures will generally, after removal of all cannulasand catheters, be in the nature of slits, for ease of understanding,they are depicted in the drawings herein more as holes. The shape of thepuncture, however, is not critical.

In order to insert plug 57, to assure that it is properly located and tobe able to hold it in place until a good seal is established, a specialinsertion apparatus has been designed. One embodiment (FIG. 1) of aninsertion apparatus according to the instant invention is comprised of asheath assembly 23, a plug holder 29 and a plug pusher 33. Sheathassembly 23, in turn, is comprised of an elongated tubular sheath 45 anda collar 35. At its rear end, collar 35 is provided with an externalthread 37. In addition, sheath assembly 23 is provided with a sheathchannel 27, which runs through the entire assembly, from front end 25,through sheath 45 and through collar 35.

Plug holder 29 is comprised of an elongated rear tubular portion 47 anda coupling 39 which has an internal thread 41. Plug holder 29 also has achannel 31 running throughout its entire length. Coupling thread 41 isdesigned to mate with collar thread 37 so that when collar 35 is screwedinto coupling 39, channels 31 and 27, which preferably are of the samecross sectional size and configuration, are aligned.

Like the other two components, the plug pusher 33 is also comprised oftwo parts, an elongated piston 49, and a stop knob 43. Piston 49 has across sectional size and configuration so as to permit sliding passageinto channels 31 and 27 with only minimal clearance. The length ofpiston 49 is such that when sheath assembly 23 and plug holder 29 arescrewed tightly together, shoulder 51 of knob 43 will abut rear end 53of plug holder 29 as front end 55 of piston 49 is aligned with front end25 of sheath 45.

It should be noted that pusher 33 is provided with its own channel 19.This is to permit passage therethrough of a guide wire and hence toenable pusher 33 to serve dual functions, as a tissue dilator and as aplug pusher.

In accordance with the method of the instant invention, first the device7 (e.g., the IAB) and the guide cannula 3 are removed, leaving the guidewire 15 in place (as seen in FIG. 6). If no guide wire has beenemployed, prior to removal of the catheter and cannula, a guide wire maybe inserted. As the cannula is withdrawn, in order to prevent bleeding,the artery is clamped, usually by pressing a finger 2 over the femoralartery upstream of the wound site. Because of this clamping, there is nosignificant blood pressure inside the artery at the site of the puncture(other than some small retrograde pressure) and the artery tends tocollapse.

Although it is believed preferable to employ a guide wire, it ispossible to practice the invention without one. It is also possible topractice the instant invention by eliminating the dilator, but this toois not the preferred approach.

The artery is clamped at least in part to prevent tissue channel 9 fromfilling with a pool of blood. When loose fibrous collagen encounters apool of blood it tends to disintegrate almost immediately. Obviously,once disintegrated it cannot function properly to seal the arterialpuncture. Hence, when collagen in loose fibrous form is employed,clamping of the artery is important. .It is less important, but stillgenerally advantageous, if the loose fibrous material has been tampeddown or otherwise compressed. As used herein, the term "loose" includesmaterial which has been compressed or tamped down.

Collagen that is more densely packed does not disintegrate uponencountering blood nearly as quickly as loose fibrous collagen.Therefore, clamping of the artery is not nearly as important when thehemostatic material is in the form of a densely packed material, as itis when a loose fleece-type hemostatic material is employed. Thus,although clamping is believed to be desireable, it is not, in all casesessential.

While the artery remains clamped, the proximal end of guide wire 15 isfed through channel 20 of tissue dilator 17. The physician can thenslide the dilator down along the guide wire into tissue channel 9 untilit reaches the wall of artery 11 (as depicted in FIG. 7).

The size and shape of the tissue dilator are such as to ensure that thebody thereof will not enter the artery. In terms of size, preferably adilator is selected which is significantly larger than the originalguide cannula 3. With respect to its shape, unlike more traditionaldilators which often have long tapered forward ends, the tissue dilator17 of the instant invention has a blunt forward end 21. Although end 21may be slightly rounded or chamfered in order to facilitate smoothpassage through tissue channel 9, it is preferable not to reduce it insize sufficiently to permit entry through the arterial puncture 13 intothe lumen of the artery.

As noted above, during this phase of the procedure, there is nosignificant blood pressure in the region of artery 11 adjacent puncture13. As a result, when end 21 of dilator t7 reaches artery 11, the wallof the artery tends to collapse further (as depicted in FIG. 7). Thephysician knows that the dilator has reached the artery because anoticeable increase in resistance is felt.

According to the procedure of the instant invention, once increasedresistance is encountered, axial pressure is maintained so as to holdend 21 of dilator 17 against artery 11. Next, a sheath 45 is passed overdilator 17 and advanced along the dilator again until increasedresistance is encountered. As with the dilator, increased resistanceindicates that front end 25 is against artery 11 (as depicted in FIG.8). In addition, a marker can be placed around the circumference of thedilator to signal when the distal end of the sheath is aligned with thedistal end of the dilator.

Because end 25 of sheath 45 is larger than arterial puncture 9, thesheath cannot enter the arterial puncture. Although the precisedimensions of dilator 17 and sheath 45 are not critical, it is believeddesirable that the sheath 45 be 30% to 50% or more larger than thepreviously removed guide cannula 3. In clinical trials done to date,when the guide cannula was 9 Fr., a 13 Fr. tissue dilator and a 14 Fr.sheath were used. It should be understood, however, that cannulae whichare oversized by as little as 10% may also be suitable.

Once the guide or procedure cannula has been removed, tissue channel 9tends to collapse. Also, once the procedure cannula and the procedurecatheter have been removed, arterial puncture 13 has a tendency to closeup. It may therefore be possible or even preferable to use a sheath thatis the same size as or even smaller than the previously removedprocedure cannula.

With the front end 25 of sheath 45 held snugly against the wall ofartery 11, plug 57 is slid down through lumen 27 of sheath 45 (as shownin FIG. 9) until it reaches end 25 of sheath 45 where it encountersartery 11. If an insertion apparatus like that shown in FIG. 1 is used,plug 57 is initially housed in plug holder 29. When it is time for pluginsertion, holder 29 is screwed onto sheath assembly 23 by means ofthreads 37 and 41, and piston 49 is inserted into channel 31.Advancement of the piston then forces plug 57 from holder 29 into sheath45 and through lumen 27 to the artery wall.

Once resistance is felt, the physician slowly withdraws the sheath whilecontinuing to maintain pressure against the piston so that plug 57remains pressed against artery 11. When shoulder 51 of knob 43 abutsrear end 53 of holder 29, the physician knows that plug 57 has beenpushed entirely Out of lumen 27 (as shown in FIG. 10). Axial pressure ismaintained for a short period of time, perhaps as little as one minuteor as long as five minutes, depending upon the circumstances, to allowplug 57 to seat in tissue channel 9 and against arterial puncture 13.Minimal axial pressure is thereafter continued while clamping pressureis slowly released until a good self-sustaining hemostatic seal has beenconfirmed. The sheath, holder, and pusher can all then be removed.

While it is believed that the preferable procedure is to permit bothpiston and sheath to remain in place until a self-sustaining hemostaticseal has been achieved, this is not absolutely necessary. Somephysicians may prefer, once the pressure of the plug against the arterywall has produced hemostasis, to withdraw the sheath so that the tissuewound may begin to close down, while maintaining pressure on the plug byuse of the piston alone. Alternatively, the piston might be withdrawnand reliance placed upon the outer rim of the sheath to hold the plugagainst the artery wall and assure hemostasis in that manner.

In addition, removal of the piston without removal of the sheath permitsinsertion of a second plug. This might be necessary where the firstplug, perhaps of a loose fibrous material, disintegrates uponencountering a pool of blood. A second plug, this one of more denselypacked material having greater physical integrity and less of a tendencytoward immediate disintegration, is inserted in the sheath and thepiston reinserted behind it.

An apparatus similar to that of FIG. 1 is depicted in FIG. 4. Theprimary difference between the two is that the plug pusher of the FIG. 4embodiment does not serve a dual function. Instead, the embodiment ofFIG. 4 has a separate tissue dilator 17 with channel 20 runningthroughout its length.

Another, somewhat different embodiment of an apparatus for inserting aplug in accordance with the instant invention is depicted in FIG. 2. Theinsertion apparatus 59 of that embodiment is made in the form of a Y,with a common or sheath leg 61, a plug leg 63 and a dilator leg 65.

In one method of using the apparatus of FIG. 2, tissue dilator 17 andinsertion apparatus 59 are preassembled by passing the dilator throughlegs 65 and 61 until enough of dilator 17 extends beyond the forward endof leg 61 to assure that end 21 will abut artery 11 before front end 2526 leg 21 reaches the surface of the patient's leg. The proximal end ofthe guide wire is then fed through dilator channel 20 and the dilator isslid down the guide wire into tissue wound 9 until end 21 of dilator 17reaches the wall of artery 11. While holding the dilator against theartery wall, the physician slides insertion apparatus 59 along dilator17 until end 26 of leg 61 reaches artery 11.

With end 26 held snugly against artery 11, dilator 17 is withdrawn, butonly far enough so as to uncover channel 67 of plug leg 63. Plug pusher69 is then moved down through channel 67 until plug 57 has enteredcommon leg 61 and pusher 69 is then withdrawn so that it will notinterfere with dilator 17 as it passes from leg 65 into leg 61.

Once plug 57 has entered leg 61 and pusher 69 has been retracted,dilator 17 is again advanced into leg 61. When resistance isencountered, the physician knows that plug 57 has reached the artery.While maintaining axial pressure on dilator 17, apparatus 59 is slowlywithdrawn until proximal end 73 of leg 65 reaches indicator mark 71. Thedistance between indicator 71 and dilator end 21 is the same as thedistance between proximal end 73 and forward end 26. Therefore, thephysician knows that when mark 71 reaches end 73, all of plug 57 hasexited from end 26 of leg 61. As was described in connection with theembodiment of FIG. 1, pressure is then maintained until a goodself-sustaining hemostatic seal has been established.

The embodiment of FIG. 3 is very similar to that of FIG. 1, except thatthe dilator and plug legs have been transposed. In the FIG. 3embodiment, plug leg 74 is coaxial with common leg 61 and dilator leg 75is at an angle, whereas in the FIG. 2 embodiment the reverse is true.

Although it is believed that the preferred method for using theembodiment of FIG. 2 is to preassembled dilator 17 in apparatus 59, thatis by no means necessary. If the physician prefers, he can just as wellinsert dilator 17 into tissue channel 9 as was described above inconnection with the embodiment of FIG. 1. He can then pass leg 61 overit. With the embodiment of FIGS. 4 and 1, while it is believedpreferable to insert dilator 17 first, the physician, if he prefers, canpreassemble the dilator in the sheath before passing the dilator overthe guide wire.

While plug 57 may be made of any resorbable material, collagen isbelieved to be most suitable. The physical form of the plug may varywidely, with the one selected by the physician being dependent upon thecircumstances of the case. For example, where the puncture wound isrelatively small and the patient has not been on high doses ofanticoagulant and heparin, a plug, like that depicted in FIG. 12a, ofloose fibrous material, somewhat like fleece or absorbent cotton oroxygenated cellulose, would serve quite well. Alternatively, for largerwounds in patients who have been on anticoagulants and heparin, it maybe necessary that the plug be able to maintain some structural integrityfor a longer period of time. Under those circumstances, a plug of moredensely packed material, as depicted in FIG. 12b, might be preferred.

A third embodiment of a suitable plug is depicted in FIG. 12c. In thatembodiment, the front end 77 of the plug might be of loose fibrousmaterial, like that depicted in FIG. 12a, whereas the remainder 79 couldbe made of a more densely packed material.

Yet another type of plug is shown in FIG. 12d. In this configuration,the front end 81 is a collagen membrane and the remainder 83 is anexpandable collagen sponge.

It is believed that when a collagen sponge or a densely packed collagenmaterial are employed, very little if any pressure need be applied afterthe initial seating of the plug. This is believed to be true because thephysical characteristics of the sponge-like or densely packed plug andthe expansion thereof, as well as its interaction with body fluids inthe tissue channel will be adequate to hold the front end against theartery wall.

It is also believed that, initially, when the plug is pressed againstthe artery, hemostasis is achieved by 0 mechanical means, i.e., byapplication of mechanical pressure all around the arterial puncture.Shortly thereafter, however, the hemostatic material begins to bind tothe arterial tissue and biochemical hemostasis takes over. Oncebiochemical hemostasis becomes sufficiently strong to withstand thenormal blood pressure within the artery, and therefore self-sustaining,external mechanical pressure can be removed.

FIG. 12e shows yet another form of plug, similar to the plug of FIG.12d, but with a lumen 85. This form of plug is designed for use byphysicians who prefer not to remove the guide wire immediately after aprocedure. The proximal end of the guide wire 15 can be fed throughlumen 85 and through the collagen membrane 81. The plug is slid downalong the guide wire through tissue channel 9 until its front endreaches the wall of the femoral artery. Indeed, the plug of FIG. 12ecould even be inserted without the use of a sheath. When the wire 15 iswithdrawn, the collagen membrane automatically reseals itself.

As noted earlier, the sheath is substantially larger in cross sectionthan is arterial puncture 13. Consequently, when plug 57, which fillsthe entire cross section of the sheath channel, reaches the artery, evenin its compressed state it overlaps puncture 13 on all sides. Obviously,then, when it exits the sheath and is permitted to expand, a fullbandage-like covering over puncture 13 is assured.

In practice it has been found that when using a collagen plug inaccordance with the subject invention, a good hemostatic seal can beachieved in five minutes or less. With larger wounds, for example, onesleft after removal of 14 Fr. or larger catheters, or after the use ofanticoagulants and heparin, sealing may take somewhat longer.

FIG. 11 depicts another means for practicing the instant invention. Inthis embodiment a piston 18 pushes ahead of its front end a closedballoon 87 formed of a collagen membrane and only partially filled witha collagen substance and a saline solution. The piston 18 has aninjection needle 18a on its front end which pierces the balloon duringthe pushing action.

After the balloon 87 exits from the sheath 23 and is pressed against thewall of the artery 11, an inflation fluid is injected via the needle 18ato fill and expand the balloon, as shown in FIG. 11, so that the ballooncovers the arterial puncture 13 and fills the region of tissue channel 9immediately adjacent the arterial puncture 13. The piston 18 isthereafter retracted to withdraw the injection needle 18a from theballoon 87. The membrane which forms the balloon 87 then automaticallyreseals itself to hold the balloon in the inflated condition shown inFIG. 11. The sheath 23 and piston 18 may then be withdrawn. When usingthis embodiment, the inflation fluid itself should be resorbable,preferably a saline solution or saline mixed with collagen in solution.

As noted above, when the procedure cannula is removed, both the arterialpuncture 13 and the tissue channel 9 tend to close up somewhat. Themethod depicted in FIG. 13 through 22 is designed to take advantage ofthis tendency. In the FIGS. 13-22 method, neither the hemostasis sheath45 nor the dilator 17 are pushed through channel 9 all the way toarterial puncture 13. Instead, as shown at 89 in FIGS. 14, 14A, 15 and15A they are inserted no further than to within about 3/4 cm. of theartery.

First, digital pressure (see arrows 105 in FIGS. 13-21) is appliedupstream of the wound so as to close down the artery (see arrows 106).In this way the pressure in the artery at the puncture site 13 is nomore than about atmospheric pressure. Although the method of thisinvention could be practiced without applying digital pressure, thatwould likely result in more profuse bleeding.

Then, as shown in FIG. 13, the dilator 17 is inserted over guide wire 15to about 3/4 cm from puncture 13. It will generally be inserted so thatbetween about 3 and about 6 cm. of its length is beneath the surface ofthe skin.

One method for assuring that the sheath is inserted to the proper depthis as follows. Once the artery 107 has been punctured and the guide wireis in place, a needle clamp 108, as is depicted in FIG. 23, is placed onthe needle 109 at the skin line 110. With the clamp in place, the needleis removed from the patient. The needle can then be placed along sidethe sheath and a mark made on the sheath to indicate the distance fromneedle tip to needle clamp. Alternatively, a mark can be made 1/2 or 3/4cm. closer to the distal end of the sheath. As yet another alternative,a kit can be provided of variable length sheaths, each having a hub atone end, and from that kit a sheath of the proper length, i.e., onehaving a total length, from hub to distal end, of 1/2 or 3/4 cm. lessthan the distance from needle tip to needle clamp can be selected.

Next, as is best seen in FIG. 14, the sheath 45 is slid down over thedilator, again stopping when its distal tip is about 3/4 cm. from thearterial puncture 13. The sheath and dilator can be inserted separately,i.e., in two steps, or together as a unit, in one step.

As can be seen in FIGS. 14a and 15a, the partially collapsed section oftissue channel 9 which is immediately adjacent puncture 13 is notreexpanded. Instead, it remains undisturbed.

The next step is to withdraw dilator 17 (as is indicated by arrow A onFIG. 15) with guide wire 15 (see FIG. 15), leaving only sheath 45 intissue channel 9. As depicted in FIG. 16, a preloaded holder orcartridge 91 with plug 93 therein is inserted (see arrow B) into sheathchamber 97. As cartridge 91 is fully seated within chamber 97, a plunger95 is used to push (see arrow C) plug 93 into and through sheath 45until the plug exits the sheath so as to cover puncture 13 and fill thatsection of channel 9 which is adjacent puncture 13 (see FIGS. 17 and17a). Simultaneously, sheath 45 is slightly withdrawn (indicated byarrows D on FIG. 17) to permit plug 93 to be fully discharged from thesheath.

Plunger 95 is then withdrawn, leaving sheath 45 to maintain pressure onplug 93. Sheath 45 can then be used to hold plug 93 in place overpuncture 13 until self sustaining hemostasis has been achieved.Alternatively, as depicted in FIG. 18, a second preloaded holder orcartridge 99 can then be inserted (see arrow E) into chamber 97. Onceagain, a plunger, 103 is used to push (see arrow F) plug 101 through thesheath. Preferably, plug 101 should be long enough so that when fullydischarged from the sheath (as depicted in FIG. 21), it will fillsubstantially all of channel 9, reaching almost to the surface of theskin.

When the front end of plug 101 reaches the end of sheath 45, it abutsplug 93. Plunger 103 is then used to force about 1 cm. of plug 101 outof the sheath (107 on FIG. 19). In this way, plug 101 takes over thefunction of holding plug 93 in place against puncture 13. While plunger103 continues to hold plug 101 in place (see arrow H), sheath 45 iswithdrawn from channel 9 (see arrows G on FIG. 20). As can be seen inFIG. 22, when sheath 45 is fully withdrawn, plugs 93 and 101 fillsubstantially all of channel 9.

It is believed to be most desireable that the front plug 93 be ofloosely packed material, while rear plug 101 be of a more densely packedmaterial. Also, as presently contemplated, in its natural., unrestrainedstate, plug 101 has a cross section larger than that of cartridge 99.Therefore, in order to get it into the cartridge, it must be compressed.It then stays in this compressed state while in cartridge 99 as well aswhile passing through sheath 45. However, after exiting from sheath 45,it naturally expands and presses against the walls of channel 9. Theinteraction then between plug 101 and the walls of channel 9 tends tohold the plug in place. As a result, very little if any externalpressure is required.

Accordingly, after only a very short period of time, perhaps almostimmediately, the plunger can be removed, leaving only the two plugs inthe wound (see FIG. 21). Pressure on the artery (see arrows 105 in FIGS.13-21) can then be released, permitting normal flow through the arteryto resume.

Although it is not necessary, in the practice of the method of theinstant invention, for plugs 93 and 101 to fill all of channel 9 fromartery to skin line,, it is believed preferable that they do so.Alternatively, plug 101 can be made longer than necessary to reach theskin line, in which case it could then be cut off flush with the skin.As yet another alternative, a single plug, the size of plugs 93 and 101combined could be used instead of two separate plugs.

While it is believed most advantageous to remove the procedure cannulaand then insert a new sheath, it would be within the scope of theinstant invention to use the procedure cannula as the delivery sheaththrough which the hemostatic material is passed.

It should also be understood that the hemostatic material employed maytake many forms. For example, it may be in the form of a liquid or itmay have a more viscous paste-like consistency. When using liquid orpaste-like materials, the delivery sheath, the hemostatic charge holderand the piston might most advantageously be combined together in asingle syringe-like device.

While the method and apparatus of this invention have been described inconnection with several specific embodiments, it should be understoodthat numerous modifications could be made by persons of skill in thisart without departing from the scope of this invention. Accordingly, theabove description is intended to be merely illustrative and notlimiting. The scope of the invention claimed should be understood asincluding all those alternatives and modifications which the abovespecification would readily suggest or which would readily occur or beapparent to one skilled in the art upon reading the above.

What is claimed is:
 1. A method for sealing a puncture in a blood vesselseparated from the skin of a patient by a layer of tissue, said layer oftissue including a tissue channel communicating between said punctureand the patient's skin, said method comprising the steps of:inserting ahemostatic material into said tissue channel, and advancing saidhemostatic material through said tissue channel to a position adjacentthe outside wall of said blood vessel in a manner such that saidhemostatic material is never freely exposed within the lumen of theblood vessel during said advancement.
 2. The method as claimed in claim1, further comprising the step of enlarging the cross-section of saidtissue channel to a cross-section greater than the cross-section of saidpuncture prior to said step of inserting said hemostatic material. 3.The method as claimed in claim 2, wherein said enlarging step enlargessaid tissue channel to a cross-section at least about 30% larger thanthe cross-section of said tissue channel prior to said enlarging step.4. The method as claimed in claim 1, wherein said hemostatic materialcomprises collagen.
 5. A method for sealing a puncture in a blood vesselseparated from the skin of a patient by a layer of tissue, said layer oftissue including a tissue channel communicating between said punctureand the patient's skin, said method comprising the steps of:inserting ahollow sheath into said tissue channel, said sheath having across-section which is larger than the cross-section of said puncture,inserting a hemostatic material into said hollow sheath; and advancingsaid hemostatic material through said hollow sheath to a positionadjacent the outside wall of said blood vessel in a manner such thatsaid hemostatic material is never freely exposed within the lumen of theblood vessel during said advancement.
 6. The method as claimed in claim5, wherein said hemostatic material comprises collagen.
 7. The method asclaimed in claim 5, wherein a guide wire extends at least from saidpuncture, through said tissue channel to the skin of the patient, saidadvancing step including the step of advancing said hemostatic materialover said guide wire through said hollow sheath.
 8. The method asclaimed in claim 5, wherein said hemostatic material comprises first andsecond charges of hemostatic material, and said advancing step includesthe steps of advancing said first charge of hemostatic material throughsaid hollow sheath to a position adjacent the outside wall of said bloodvessel, and advancing said second charge of hemostatic material throughsaid hollow sheath to a position proximate said first charge ofhemostatic material.